The invention concerns a doctor device, notably for use with machines for coating paper or cardboard. The doctor device has a relatively bendable, flexible, tape-type thin and line-shaped doctor element fitted or held in or on a separate holder. Such a device is known from DE-OS 2,822,682. Here, a so-called blade, whose trailing edge (longitudinal edge) forms the dosing, or smoothing edge, is movably mounted in the holder. The blade may be fashioned as a long strip so that, by a movement along the surface of the backing roll carrying the paper web, a continuous change of its working area may be imparted.
A device according to EP 0 109 520 is a dosing system for coating mixture used to coat webs of paper or cardboard. It has a holder in which a doctor strip is mounted in a guide slot. The doctor strip has a slightly flexible design in that it features on its back side numerous parallel incisions forming sort of a comb strip. The doctor surface proper is convex and ends in an abrupt edge, which is a major feature of this device. The working surface of the doctor strip is smooth and, due to its abrupt leaving edge, not suited to be provided with grooves to enable a volumetric dosing. Furthermore, the doctor strip is a relatively expensive element, which is a disadvantage when repeated replacement is required.
The problem underlying the present invention is to provide a doctor device which allows a very universal use, has a long service life in terms of wear and can be made at relatively low cost.